"like cures like" is a dangerous oversimplification.
Vaccines and immunotherapy work by giving the body small amounts of the actual thing that is harmful (usually dead, in the case of vaccines). It's easy to see why this is a reasonable approach - it's giving the body "sparring practice" against the disease or substance.
Antivenom works similarly, except that the antibodies are grown in another animal, probably because by the time someone is bitten, there isn't time for their bodies to learn how to produce it themselves.
Homeopathy is based around finding substances which cause similar symptoms. They have no relation to the actual cause of the condition that they're supposed to treat. Is the "cure" for Ebola any random chemical that happens to cause humans to bleed out of every orifice? Is the "cure" for Alzheimer's any random chemical that causes people to lose their memory? How many conditions cause headaches, or nausea, or lack of energy? Are we supposed to believe that anything which can cause those symptoms is a universal cure for all of those conditions? If so, why bother with snake oil at all? Just make sure that one is exposed to a variety of cold/flu viruses, and they should (according to the "like symptoms" "theory") cancel each other out.
The whole concept didn't make sense in the 19th century, and it certainly doesn't today.